1. Field of the Invention
The present invention relates to an information processing apparatus, an information processing method, a program, and a recording medium recording the program and readable by the information processing apparatus, and more particularly, to an information processing technique for outputting an image used for determining the acceptable colorant amount of a print medium. In addition, the present invention relates to a color separation table generation method and an information processing apparatus, and more particularly, to a technique for generating a color separation table used for converting an image signal into a signal representing the amount of a colorant, such as ink, in association with a recording medium used for recording.
2. Description of the Related Art
Generally, a color separation table (lookup table (LUT)) is used in processing for converting a color signal representing image data into a color signal representing a colorant, such as ink or toner, used in a recording apparatus, such as a color printer. In the color separation table, for example, ink values (ink amounts) of yellow (Y), magenta (M), cyan (C), and black (K), which are color signals representing ink, are stored as grid point data at grid points defined by the values of R, G, and B color signals.
In a method for generating a color separation table, a cube constituted by grid points in an RGB color space is divided into six tetrahedrons each having four apexes from among the apexes of the cube. Ink amounts (grid point data) of grid points on sides forming each of the four triangles constituting each of the tetrahedrons are defined in advance. Then, the ink amounts corresponding to grid points inside each of the tetrahedrons other than the grid points on the sides are calculated by interpolation using the ink amounts corresponding to the grid points on the sides. In general, when a printing apparatus does not hold a color profile supporting a print medium, the printing apparatus is not capable of performing printing in accordance with the colorant amount optimal for the print medium. Thus, a normal printed result cannot be achieved. Consequently, an acceptable colorant amount depending on a print medium must be appropriately set, and a color profile must be generated such that the acceptable colorant amount is not exceeded.
In general, in an image recording apparatus, such as a printer, a maximum colorant amount, which is a printable colorant amount per unit area, depending on a recording medium is defined, and a color separation table (color profile) is prepared such that the maximum colorant amount is not exceeded. This is because some commercially available recording media, such as recording paper, cannot absorb the colorant amount that can be printed per unit area by a commercially available color printer.
For example, when a recording apparatus, such as a printer, prints a color image, Y, M, C, and K colorants are used in a superimposing manner. Thus, the total amount of colorant used tends to be increased. In this case, for an inkjet printer, ink cannot be fully absorbed depending on the ink absorption characteristics of recording paper, and ink overflow or bleeding may occur. Thus, accurate density may not be achievable.
In addition, for an electrophotographic printer using toner, the toner might not adhere to recording paper depending on the toner adhesion characteristics of the recording paper. Thus, accurate density may not be achievable. As a result, even if excellent image reproduction is achieved in image processing for generating colorant data, accurate image reproduction may not be achievable as the actual recorded result.
Under such circumstances, a technique is disclosed in US 2004/0027406 in which in order to achieve printing corresponding to the colorant amount optimal for a print medium even when a color profile supporting the print medium is not held by a printing apparatus, a test pattern for determining an ink ejection amount is generated. For example, a technique is known in which, for calorimetric color separation, a calorimetric patch is generated in consideration of the maximum colorant amount such that the maximum colorant amount is not exceeded and color separation optimal for a printer and recording paper is performed. Thus, a patch is recorded such that excess addition of a colorant, such as ink or toner, does not occur, and an accurate color separation table can be generated.
However, in the method disclosed in US 2004/0027406, since there is no limitation in the range of ink ejection amount used for determination of an acceptable colorant amount, a large number of test patterns must be printed. In addition, since a plurality of various patterns are combined to generate the large number of test patterns, when the determination is performed, technical knowledge about the determination and significant time and effort are required. Thus, when a user who has little technical knowledge of the acceptable colorant amount of a print medium performs printing on a desired print medium whose color profile is not provided, a printed result with an optimal colorant amount cannot be achieved.